Detection rate of colonic polyp among patients who had undergone colonoscopy at gastroenterology unit of Serdang Hospital, Malaysia

ABSTRACT

Objective: The aim of this study was to evaluate the demography, and to determine the detection rate of polyps, and detection rate of adenoma at a Malaysian tertiary hospital.

Methods: This is a retrospective study of all the patients who had undergone colonoscopy at Gastroenterology endoscopy unit, Serdang Hospital from 1st January 2010 to 31st December 2016. Patients who had a history of colorectal cancer, polyp or inflammatory bowel disease were excluded. Data collected which included patients’ demography, indication for colonoscopy, colonoscopy finding, and histopathology results. Data was analysed with SPSS version 16.

Results: Among the 559 patients who had fulfilled the inclusion criteria (68 males, 44 females), 112 patients were found to have at least one polyp giving the polyp detection rate (PDR) of 20% and 168 polypectomies were performed. The PDR among male patients was higher than that of females (22.5% vs 17.1%, p<0.05). The detection rate of polyp was nearly equal in Malays, Chinese, Indians, and Others. The polyps were more common in those of age 40 years old and above (p<0.05), with the mean age of 63.0±1.5 years. The commonest morphology of polyp in our patients was sessile (58%) and majority was medium size (5-9mm). Otherwise, the polyps were commonly found in the distal colon those that in proximal colon (55.3% vs 38.7%, p<0.05). The adenoma detection rate (ADR) was 19.1% (107/559). Conclusion: The detection rate of colonic polyp from colonoscopy is 20% in our centre.

KEY WORDS:

Colorectal cancer, colonoscopy, screening, Malaysia, polyp detection

INTRODUCTION

Colorectal cancer (CRC) remains as one the most common form of gastrointestinal cancer around the world. The number of cases of colon cancer has been on the rise in Asian countries over the past few years.1 _{In Malaysia, CRC is the} second most common cancer in males and third most

common cancer in females.2_{The increasing number of cases} has directly increased with the economic burden in regard to direct medical care and non-medical cost. It has been estimated that the cost of management of new cases of CRC could reach up to MYR108 millon per year.3

In fact, it is the fourth leading cause of mortality in the world and has account for 8-12% of mortality in the world with estimated 1.4 million new cases a year.4 _{Most colorectal} carcinoma arises from the progression of adenoma from small to large polyps and then to dysplasia and carcinoma. On average, it takes at least 10 years for this progression.5 Given that the slow and long duration in the process of conversion of colorectal adenomas into adenocarcinoma, early detection and colonoscopic removal of these precancerous polyps are very effective in reducing the incidence and mortality rate of CRC in long run.6

Recent studies have shown that endoscopic procedures of the colon could half the risk of developing colorectal carcinoma and its protective benefit could last as long as six years.7_The ASGE/ACG taskforce on quality in endoscopy have recommended that adenoma detection rates of 15% or higher for female patients and 25% or higher for male patients as indicators of adequate colonoscopy quality.8

METHODS

This is a retrospective cross section study of all patients who had undergone colonoscopy at the Gastroenterology Endoscopy Unit (GEU), Serdang Hospital from the 1st January 2010 to 31st December 2016. The records of the patients were traced from Hospital Information System (EHIS). Data such as patient gender, age, ethnicity, indication for colonoscopy, colonoscopic finding and complication, histopathology finding of polyps were extracted and further analysed. The analysis was done using EXCEL and SPSS for Windows version 16.0. Categorical variables are expressed as numbers and percentages. χ2_{or Fisher’s exact test, where appropriate,} was used for analysis of categorical variables. A two-tailed p<0.05was considered statistically significant.

Patients included in the study were those with follow up at own Gastroenterology and Hepatology Clinic, Serdang Hospital, and patients who were internally referred from

Detection rate of colonic polyp among patients who had

undergone colonoscopy at gastroenterology unit of

Serdang Hospital, Malaysia

Tan Yi Jun, MRCP1_{, Wendy Tan, MRCP}1_{, Chieng JinYu, FRCP}2

1_{Medical Department, Hospital Serdang, Selangor, Malaysia,} 2_{Medical Department, Faculty of Medicine and Health Sciences,} Putra University of Malaysia, Selangor, Malaysia

Detection rate of colonic polyp among patients who had undergone colonoscopy

other departments such as General Medical Department, General Surgical Department, and referrals from local district hospitals and clinics. All the colonoscopies were performed by our three qualified gastroenterologists, with sedation of midazolam and fentanyl. Informed consents were obtained

prior the colonoscopy. The average withdrawal time during colonoscopies was at least six minutes. Only those with complete colonoscopy (successful caecal intubation) were included in this study. Indications for colonoscopy included CRC screening, anaemia, chronic constipation, chronic diarrhoea, per rectal bleeding, and others (persistent abdominal pain, unexplained weight loss). Those who had colonic polyps were further analysed according to the polyp’s size (small, medium, and large), morphology (pedunculated, sessile, circumferential), histopathology (non-adenoma/hyperplastic, adenoma, serrated, juvenile, adenocarcinoma, and inflammatory), and location (proximal colon including caecum, ascending colon and transverse colon; distal colon including descending colon, sigmoid colon and rectum; and entire colon). We have looked into complications of colonoscopy including post polypectomy bleeding, complications from over sedation and bowel perforation.

Both Polyp Detection Rate (PDR) and Adenoma Detection Rate (ADR) were accounted. The PDR was defined as the proportion of procedures in which at least one polyp was found over the total number of colonoscopies. ADR was defined as the number of colonoscopies in which at least one adenoma was found, divided by the total number of colonoscopies performed.

Patients who were excluded from our study either had incomplete colonoscopy (caecal intubation was not achieved during the colonoscopy due to poor bowel preparation, looping, pain intolerance, prior surgery with adhesions and altered anatomy), or incomplete data, or those who had polyps/Colorectal cancer/Inflammatory bowel disease/colonic resection before or repeated colonoscopy for previous incomplete colonoscopy.

This study was registered in accordance with the National Medical Research Register Malaysia (NMRR-17-2494-37735 (IIR).

Table I: Characteristics of the patients whom have undergone Colonoscopy

Variable n(%), total 559

Gender

Male 302(54.0%)

Female 257(46.0%)

Ethnicity

Malay 238(42.6%)

Chinese 224(40.1%)

Indian 79(14.1%)

Others 18 (3.2%)

Age group

<20 19 (3.4%)

20-39 78 (14.0%)

40-59 167 (29.9%)

60-79 281 (50.2%)

>80 14 (2.5%)

Indications of screening

CRC screening 157(28.1%)

Anaemia 208(37.2%)

Chronic constipation 49 (8.8%) Chronic diarrhea 75(13.4%)

PR Bleed 40 (7.1%)

Others (abdominal pain,

Unexplained weight loss) 30 (5.4%)

Table II: Detection Rate of Polyps according to Gender/Ethnicity/Age group

Variable n(%) P value

PDR 112/559(20.0%)

Gender p<0.05

Male 68/302(22.5%)

Female 44/257(17.1%)

Ethnicity p<0.05

Malay 47/238(19.7%)

Chinese 45/224(20.1%)

Indian 18/79(22.8%)

Others 2/18(11.1%)

Age group p<0.05

<20 2/19 (10.5%)

20-39 10/78 (12.8%)

40-59 36/167 (21.6%)

60-79 60/281(21.3%)

>80 4/14 (28.6%)

<4012/97 (12.4%)

40 years old and above 100/462 (21.6%)

Table III: Characteristic of polyps

Variable n(%), total 168 P value

Size

Small (<5mm) 50(29.7%) Medium (5 – 9 mm) 70(41.7%) Large (>10mm) 48(28.6%)

Morphology

Pedunculated 62(36.9%)

Sessile 97(57.7%)

Circumferential 9(5.4%)

Histopathology

Non-adenoma/Hyperplastic 30 (17.9%) Adenoma (Total) 107 (63.7%)

- Tubular 52

- Tubulovillous 48

- Villous 7

Serrated 7 (4.2%)

Juvenile 3 (1.8%)

Adenocarcinoma 13 (7.7%) Inflammatory 8 (4.7%) Location

Caecum 21 (12.5%)

Ascending colon 22 (13.1%)

Transverse colon 22 (13.1%) Distal colon Descending colon 40 (23.8%) vs Proximal colon Sigmoid colon 32 (19.0%) 55.3% vs 38.7%,

Rectum 21(12.5%) p<0.05

Entire Colon 10 (6.0%)

RESULTS

A total of 725 colonoscopies were performed at our GEU with 92% (669/725) of successful caecal intubation rate. However, only 559 of them (77.0%) were recruited to our study. Distributions of male and female subjects was 54% and 46% respectively. The ethnicity distribution of our patients was Malays (42.6%), Chinese (40.1%), Indians (14.1%) and others (3.2%). Their ages were between age 60-79 years. Anaemia was the most common indication for colonoscopy (37.2%). The characteristics of the patients in this study is summarized in Table I.

Among the 559 patients, a total of 112 patients were found to have at least one polyp. The overall estimate of PDR was 20.0% (112/559), with 168 polypectomies performed. The PDR among the male patients was significantly higher than that of female patients (22.5% vs 17.1%, p<0.05) as shown in Fig 1. Detection rate of polyps among the ethnicity were nearly equal (Malay 19.7%, Chinese 20.1%, Indian -22.8%, p<0.05) as shown in Table II. Polyps were more commonly detected in those age 40 years old and above (age less than 40 years old 12.4%, Age 40 years old and above 21.6%, p<0.05) as shown in Fig 2. The mean age of patients with polyp was 63.0±1.5 years. We found that the commonest morphology of polyp in the patients was sessile (57.7%) and the majority (41.7%) were medium size (5-9mm). Three patients had multiple polyposis coli over entire large bowel. Otherwise, the prevalence of polyps in distal colon was higher than that in proximal colon (55.3% vs 38.7%, p<0.05). Majority of the polyps were located in the recto sigmoid

region (31.5%) followed by descending colon (23.8%), ascending (13.1%), transverse colon (13.1%) and caecum 12.5%.

The ADR in this study was 19.1% (107/559). 63.7% of the polyps detected were adenomas which consist of tubular 48.6%, tubulovillous 44.9% and villous 6.5%. (Table III). This was followed by non-adenoma/hyperplastic 17.9%, adenocarcinoma 7.7%, inflammatory 4.8%, serrated 4.2% and juvenile 1.8%.

Only two patients (0.3%) developed complications from colonoscopies, one developed side effect of sedation which required intubation, and another developed bleeding post polypectomy which was treated endoscopically. No mortality was reported during colonoscopy procedures.

DISCUSSION

Based on the colonoscopies findings, our overall estimate for PDR was 20.0% while ADR was 19.1%. The PDR was similar to reports from the Middle East.9-11_{However, the PDR and ADR} rates in this study was comparatively low when compared with figures from Western and some East Asian Countries.12-18 Compared to African countries (PDR, 16.1%; ADR, 6.8%), both of our PDR and ADR rates were reported to be higher.19 We inferred from our study that male gender and older age were the strong indicators for occurrence detection of colonic polyp.

Male gender was believed to have a higher impact on prevalence of either colonic polyp or CRC. Moreover, it was detected that advanced neoplasia was at a significantly higher rate in men than in women, which may warrant refinement of the screening recommendations for CRC.20,21 This could be explained by the lifestyle, especially red meat intake and smoking habit, which were very common among males. Woman on the other hand perhaps had hormonal changes and some may even be on contraceptives or hormonal pills which somehow protect them from the risk of colonic polyp or CRC.22

Age was another strong risk factor for colonic polyp or CRC, and older age is the most important predictor for the prevalence of adenomas and cancer. In our study, most of

Fig. 1: Detection Rate of Polyps According to Gender.

Fig. 3: Detection Rate of Polyps according to Age Group.

Detection rate of colonic polyp among patients who had undergone colonoscopy

our patients were in the age 40 years old and above, and 28.6% of those were more than 80 years old were found to have polyp during the colonoscopy. This finding was consistent with the literature where the increased prevalence of colonic polyp was with increasing age.23

Ethnic differences had been reported for colorectal polyps and large bowel cancer; although the supporting data was weak and inconclusive. Malaysia is a multiracial country consisting of Malays, Chinese, Indians and numerous indigenous people, and our patients’ ethnicity distribution was Malays (42.6%), Chinese (40.1%), Indians (14.1%) and others (3.2%). Each ethnicity had its own religion, festivals, food and customs. However, we show that PDR in all the ethnicity was nearly equal being about 20%. This corresponded to a cross-sectional study among different racial patients among Asians attending for colonoscopy over a 41-month period in a private endoscopy centre and they had concluded that race did not appear to be an important factor.24

In our study, the vast majority of the polyps were found at distal colon located over recto sigmoid region (31.5%) followed by descending colon (23.8%). This correspond to other studies that showed that distal colon was more prone to develop polyps than proximal colon.25-27_{This could be further} explained by the environmental factors that could potentially lead to the development of distal colon polyps or tumours such as diet, physical activity, smoking, history of cholecystectomy, chemoprophylaxis agents, reproductive and hormonal status.

The commonest histopathology of polyp in our patients was adenomas (62.5%), followed by hyperplastic (17.9%) and others (19.6%). Study shows that adenomatous polyps were the precursors of most CRC.28 _{Our results were similar to} National Polyp study, in which 66.5% of the polyps removed in 2362 patients were adenomatous.29

Majority (42%) of the polyps from our study was medium size (5-9mm). In fact, polyp size is an important biomarker that correlates with its risk of cancer and guides its clinical management.30

Retrospective study had its own weakness, that certain data, such as endoscopy withdrawal time, timing of the procedure, and bowel preparation were unable to be standardized. However, the retrospective design also was a strength on the opposite view, that it provided information in our actual clinical practice. It reduces the biases of highly controlled studies, in which the colonoscopy can be performed more diligently than during routine practice. This study was not population-based; therefore, our patients could have the bias in selection. Moreover, our samples included mostly symptomatic patients, in which the estimates may be different from screening studies with asymptomatic individuals. Family history was also not studied in this study due to unstandardized retrospective study.

CONCLUSION

In conclusion, the PDR was 20% and ADR is 19.1% in the Serdang Hospital . Gender and age were the most important predictors for the prevalence of adenomas while PDR in all the ethnicity were nearly equal.

ACKNOWLEDGEMENTS

We would like to thank all supporting staff from the Gastroenterology Endoscopy unit, Serdang Hospital for assistance in data collection and comments that greatly improved the manuscript. We would also like to thank the Director General of Health Malaysia his permission to publish this paper.

CONFLICT OF INTEREST

All authors declare no competing conflict of interest.

FINANCIAL DISCLOSURE

The authors declare that this study has received no financial support.

REFERENCES

1. Sung JJ, Lau JY, Goh KL, Leung WK, Asia Pacific Working Group on Colorectal Cancer. Increasing incidence of colorectal cancer in Asia: implications for screening. Lancet Oncology 2005; 6(11): 871-6. 2. Veetil SK, Lim KG, Nathorn C, Ching SM, Abu Hassan MR. Colorectal

cancer in Malaysia: Its burden and implications for a multiethnic country. Asian J Surg 2017; 40(6): 481-9.

3. Natrah MS, Sharifa Ezat WP, Syed MA, Mohd AM, Saperi S, Ismail S et al. Economic evaluation of monoclonal antibody in the management of colorectal cancer in Malaysia. BMC Health Serv Res 2012; 12 (Suppl 1): 3. 4. Ferlay J, Soerjomataram I, Dikshit R, Eser S, Mathers C, Rebelo M et al. Cancer incidence and mortality worldwide: sources, methods and major patterns in GLOBOCAN 2012. Int J Cancer 2015; 136(5): E359-86. 5. Winawer SJ, Fletcher RH, Miller L, Goodlee F, Stolar MH, Murlow CD et al.

Colorectal cancer screening: clinical guideline and rationale. Gastroenterology1997; 112(2): 594-642.

6. Zauber AG1, Winawer SJ, O'Brien MJ, Lansdorp-Vogelaar I, van Ballegooijen M, Hankey BF et al. Colonoscopic polypectomy and long-term prevention of colorectal cancer deaths. N Engl J Med 2012; 366(8): 687-96.

7. Muller AD, Sonerberg A. Prevention of colorectal cancer by flexible endoscopy and polypectomy, a case-control study. Ann Intern Med 1995; 123(12): 904-10.

8. Rex DK, Petrini JL, Baron TH, Chak A, Cohen J, Deal SE. Quality indicators for colonoscopy. AM J Gastroenterol 2006; 101(4): 873-85.

9. Hamid AA, Ehsan NM, Sara Ashtari, Mohmad AP, Vahid C, Fakhrosadat A et al. Polyp detection rate and pathological features in patients undergoing a comprehensive colonoscopy screening. World J Gastrointest Pathophysiol 2017; 8(1): 3-10.

10. Al-Enezi SA, Alsurayei SA, Ismail AE, Aly NY, Ismail WA, Abou-Bakr AA. Adenomatous colorectal polyps in patients referred for colonoscopy in a regional hospital in Kuwait. Saudi J Gastroenterol 2010; 16(3): 188-93. 11. Ashktorab H, Brim H, Al-Riyami M, Date A, Al-Mawaly K, Kashoub M et

al. Sporadic colon cancer: mismatch repair immunohistochemistry and microsatellite instability in Omani subjects. Dig Dis Sci. 2008; 53(10): 2723-31.

12. Nayagam S, Selvapatt N, Auguste JL, Williams HRT, Orchard TR, Thomas HJW et al. Quality of colonoscopic procedures among independently practising gastroenterology trainees in a NW London cohort: are they reaching national standards? Gut 2012; 61: A59-60.

13. Lucendo AJ, Guagnozzi D, Angueira T, González-CS, Fernández-FM, Friginal-RAB et al. The relationship between proximal and distal colonic adenomas: is screening sigmoidoscopy enough in the presence of a changing epidemiology? Eur J Gastroenterol Hepatol 2013; 25(8): 973-80. 14. Boroff ES, Gurudu SR, Hentz JG, Leighton JA, Ramirez FC. Polyp and adenoma detection rates in the proximal and distal colon. Am J Gastroenterol 2013; 108(6): 993-9.

15. Gao R, Corbett GD, Lee J, Sampaziotis F, Cameron E. Adenoma detection reduces during a colonoscopy list. Gut 2012; 61: A21.

16. Chung SJ, Kim YS, Yang SY, Song JH, Park MJ, Kim JS et al. Prevalence and risk of colorectal adenoma in asymptomatic Koreans aged 40-49 years undergoing screening colonoscopy. J Gastroenterol Hepatol 2010; 25(3): 519-25.

17. Kazuhiro K, Nagamu I, Toshifumi Y, Rieko B, Kazuaki Y, Hiroyuki I et al. Polyp detection rate in transverse and sigmoid colon significantly increases with longer withdrawal time during screening colonoscopy. PLoS ONE 2017; 12(3): e0174155.

18. Leung WK, Tang V, Lui PC. Detection rates of proximal or large serrated polyps in Chinese patients undergoing screening colonoscopy. J Dig Dis 2012; 13(9): 466-71.

19. Alatise OI, Arigbabu AO, Agbakwuru AE, Lawal OO, Sowande OA, Odujoko OO et al. Polyp prevalence at colonoscopy among Nigerians: A prospective observational study. Niger J Clin Pract 2014; 17(6): 756-62. 20. Bafandeh Y, Daghestani D, Esmaili H. Demographic and anatomical

survey of colorectal polyps in an Iranian population. Asian Pac J Cancer Prev 2005; 6(4): 537-40.

21. Hoffmeister M, Schmitz S, Karmrodt E, Stegmaier C, Haug U, Arndt V et al. Male sex and smoking have a larger impact on the prevalence of colorectal neoplasia than family history of colorectal cancer. Clin Gastroenterol Hepatol 2010; 8(10): 870-6.

22. Bashar JQ, Susan C, Michael BW. The Effect of Polyp Location and Patient Gender on the Presence of Dysplasia in Colonic Polyps. Clin Transl Gastroenterol 2012; 3(7): e20.

23. National Cancer Institute. SEER Data 1973-2015 (including July-December 2005 Hurricane Katrina impacted Louisiana cases). [cited June 2017]. Available from: https://seer.cancer.gov/data/.

24. Rajendra S, Ho JJ, Arokiasamy J. Risk of colorectal adenomas in a multiethnic Asian patient population: race does not matter. J Gastroenterol Hepatol 2005; 20(1): 51-5.

25. Delavari A, Mardan F, Salimzadeh H, Bishehsari F, Khosravi P, Khanehzad M et al. Characteristics of colorectal polyps and cancer; a retrospective review of colonoscopy data in Iran. Middle East J Dig Dis 2014; 6(3): 144-50.

26. Almadi MA, Alharbi O, Azzam N, Wadera J, Sadaf N, Aljebreen AM. Prevalence and characteristics of colonic polyps and adenomas in 2654 colonoscopies in Saudi Arabia. Saudi J Gastroenterol 2014; 20(3): 154-61. 27. Eshghi MJ, Fatemi R, Hashemy A, Aldulaimi D, Khodadoostan M. A retrospective study of patients with colorectal polyps. Gastroenterol Hepatol Bed Bench 2011; 4(1): 17-22.

28. Muto T, Bussey HJ, Morson BC. The evolution of cancer of the colon and rectum. BCCancer 1975; 36(6): 2251-70.

29. O'Brien MJ, Winawer SJ, Zauber AG, Gottlieb LS, Sternberg SS, Diaz B et al. The National Polyp Study. Patient and polyp characteristics associated with high-grade dysplasia in colorectal adenomas. Gastroenterology 1990; 98(2): 371-9.